Method and System for Disengaging a Shrink Coupling on a Turbine Generator

ABSTRACT

A system and associated method for disengaging a shrink coupling that secures a shaft to a drive train component, such as a gearbox, includes a reaction plate erected around the shaft at a location displaced from the shrink coupling, with the reaction plate being anchored in place relative to the shaft. A plurality of jacking devices, such as hydraulic jacks, are operationally disposed between the reaction plate and shrink coupling and spaced circumferentially around the shaft. The jacking devices have a first end engaged against the reaction plate and a second opposite end mechanically fastened to the shrink coupling. To remove the shrink coupling from the drive train component, the shrink coupling is released from its clamped state and the jacking devices are activated to exert a pulling force on the shrink coupling, which causes the shrink coupling to be pulled off of the drive train component and moved axially along the shaft to a resting position on the shaft.

CROSS-REFERENCE TO RELATED APPLICATION

The present invention is a Divisional Application of U.S. patentapplication Ser. No. 12/566,952, filed Sep. 25, 2009.

FIELD OF THE INVENTION

The present invention relates generally to a method and related systemfor disengaging a shrink coupling, and, more particularly, to removal ofa shrink coupling used to couple a main shaft to gearbox in a turbinegenerator.

BACKGROUND OF THE INVENTION

Shrink couplings (also known as “shrink disks”) are widely used in drivetrains to couple a rotating shaft to another component, such as agearbox. In many conventional wind turbine designs, a shrink coupling isused to secure the main drive shaft (“low speed shaft”) to the gearbox.This coupling can be quite large, often weighing in the range of about2,000 lbs, and various maintenance procedures require removal of theshrink coupling. For example, inspection or replacement of the low speedshaft seal (also referred to as the “front seal”) in the gearbox canonly be accomplished with removal of the shrink coupling.

Modern wind turbines can be quite large, with many designs having arotor height exceeding 100 meters, and maintenance of these windturbines often requires the use of a large construction crane in orderto repair/replace components in the turbine nacelle. Removal of the maindrive shaft shrink coupling is an example of just such a procedure that,to date, typically requires a crane. The logistic requirements, turbinedown time, and expense associated with this maintenance procedure can betremendous.

Wind power is considered one of the cleanest, most environmentallyfriendly energy sources presently available, and wind turbines havegained increased attention in this regard. However, the cost/benefiteconomics of wind energy is a constant consideration. The cost ofproducing the energy, including maintenance of the wind turbines, cannotoutweigh the benefits. In this regard, the industry would benefit fromimprovements or advancements in wind turbine operation and maintenancethat would reduce the requirements (and associated expense andlogistical burdens) for an on-site crane in the performance ofmaintenance or repair work on the turbines.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

Although aspects of the invention will be described herein as theyrelate to maintenance procedures on a wind turbine, it should beappreciated that this is for purposes of illustrating particular usefulembodiments of the present method and system for removal of a shrinkcoupling. The invention is not limited to wind turbines, and isapplicable in any situation that requires removal of a relatively largeshrink coupling from between a shaft and another component.

In accordance with aspects of the invention, a method is provided fordisengaging a shrink coupling that secures a shaft to a drive traincomponent. The method includes erecting a reaction plate around theshaft at a location axially displaced from the shrink coupling such thatthe reaction plate is anchored axially in place relative to the shaft. Ashim member may be placed around at least a portion of the circumferenceof the shaft in an axial position between the shrink coupling andreaction plate. A plurality of jacking devices are disposed between thereaction plate and the shrink coupling and are equally circumferentiallyspaced around the shaft. The jacking devices have a first end engagedagainst the reaction plate and a second, opposite end in apull-engagement configuration with the shrink coupling. The shrinkcoupling is released from its clamped state, and the jacking devices areactivated to exert a pulling force on the shrink coupling to pull thecoupling off of the drive train component and axially along the shaft toa resting position on the shaft. If used, the shim member is configuredso that the shrink coupling remains concentrically aligned with thedrive train component in its rest position on the shaft for subsequentre-engagement with the drive train component.

The present invention also encompasses a system for disengaging a shrinkcoupling that secures a shaft to a drive train component. The systemincludes a reaction plate erected around the shaft at a locationdisplaced from the shrink coupling and anchored axially in placerelative to the shaft. A shim member may be disposed circumferentiallyaround at least a portion of the circumference of the shaft at an axiallocation between the shrink coupling and the reaction plate. A pluralityof jacking devices are operationally disposed between the reaction plateand the shrink coupling. The jacking devices are equallycircumferentially spaced around the shaft and have a first end engagedagainst the reaction plate and a second, opposite end mechanicallyfastened to the shrink coupling in a pull-engagement configuration. Withthis system, the shrink coupling can be released from its clamping stateand removed from the drive train component by activating the jackingdevices, which exert a pulling force on the shrink coupling to pull thecoupling off of the drive train component and axially along the shaft toa resting position on the shaft.

The invention also includes a method for performing a maintenanceprocedure on a front seal of a turbine generator gearbox wherein a driveshaft is coupled to the gearbox with a shrink coupling. The methodincludes erecting a reaction plate around the drive shaft at a locationaxially displaced from the shrink coupling. A plurality of jackingdevices are disposed between the reaction plate and the shrink coupling,with the jacking devices being circumferentially spaced around theshaft. The jacking devices have a first end that is engaged against thereaction plate, and a second opposite end configured in apull-engagement configuration with the shrink coupling. The shrinkcoupling is released from its clamped state and the jacking devices areactivated to exert a pulling force on the shrink coupling. The pullingforce causes the shrink coupling to be pulled off of the gear boxaxially along the shaft to a resting position on the shaft. In thismanner, access is provided to the front seal for the maintenanceprocedure. Once the maintenance procedure on the front seal has beenperformed, the shrink coupling is moved from its rest position on theshaft back into position for securing the shaft to the gearbox byreversing the direction of the jacking devices and moving the shrinkcoupling axially along the shaft to an operational position on thegearbox. The shrink coupling is then activated into its clamped state.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a perspective view of a conventional wind turbine;

FIG. 2 is a perspective view of an embodiment of a system in accordancewith aspects of the invention configured for removal of a shrinkcoupling from a turbine generator gearbox;

FIG. 3 is a perspective view of an alternate embodiment of a system inaccordance with aspects of the invention configured for subsequentre-attachment of a shrink coupling on a turbine generator gearbox;

FIGS. 4 through 6 are sequential operational views of a process forremoving a shrink coupling from a turbine generator gearbox inaccordance with the invention; and,

FIGS. 7 through 9 are sequential operational views of a process forsubsequent re-attachment of a shrink coupling onto a turbine generatorgearbox.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, and not as alimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment, can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

FIG. 1 illustrates a wind turbine 10 of conventional construction. Thewind turbine 10 includes a tower 12 with a nacelle 14 mounted thereon. Aplurality of turbine blades 16 are mounted to a rotor hub 18, which isin turn connected to a main flange 20 that turns a main rotor shaft 22.The main rotor shaft 22 is coupled to a gearbox 30 via a shrink coupling32, which generates a compression fitting between a sleeve 31 (FIGS. 4Cand 5A) in the gearbox 30 and the shaft 22. The gearbox 30 is connectedto a generator 15 via a high speed shaft (not shown). The blades 16convert motive force of wind into rotational mechanical energy via theshaft 22 and gearbox 30 to generate electricity with the generator 15.

FIG. 2 illustrates components of a wind turbine generator supported by abedplate 28. As discussed, the bedplate 28 and generator components maybe housed within a nacelle 14 (FIG. 1). Briefly, the main rotor shaft 22is supported by a bearing 24 relative to the bedplate 28. A main flange20 is attached to the shaft 22 at the forward end thereof and connectswith a rotor hub 18 of the wind turbine 10 (FIG. 1). The opposite end ofthe main rotor shaft 22 is coupled to a gearbox 30 via a shrink coupling32. In the embodiment illustrated, the shrink coupling 32 is aconventional dual-ring coupling that may be hydraulically actuated. Anumber of head bolts 34 (which may include jacking screws) are locatedaround a front face of the shrink coupling 32 and are used forinstallation and actuation of the shrink coupling 32. Operation ofshrink couplings 32 is well known by those skilled in the art and adetailed explanation thereof is not necessary for purposes of thepresent disclosure.

Any number of other components related to the turbine generator drivetrain or operation of the wind turbine may be configured on the bedplate28, for example yawl drives 26, control equipment, coolers, and thelike. The perspective view of FIG. 2 is provided for illustrativepurposes only, and the invention is not limited to any particular typeof drive train or other equipment configuration within a nacelle 14 orother structure.

Still referring to FIG. 2, a system 35 in accordance with aspects of theinvention is provided for removing the shrink coupling 32 from a drivetrain component, such as the gearbox 30. The system 35 includes areaction plate 36 that is erected around the shaft 22 at a location thatis axially displaced from the front face of the shrink coupling 32. Thereaction plate 36 is anchored relative to the bedplate 28 at anchorlocations 38 by any conventional means so that the reaction plate 16 isaxially fixed in position relative to the shrink coupling 32. Thereaction plate 36 may be formed from a plurality of individual framemembers that are mechanically fastened together by any conventionalmeans. In the illustrated embodiment, the reaction plate 36 includes aforward-most section 41 that extends partially around the circumferenceof the shaft 22 and is anchored to the bedplate 28 at anchor points 38,and a head plate 40 that extends completely around the shaft 22. Thehead plate 40 may be connected to the forward section 41 by anyconventional means.

A plurality of jacking devices 42 are disposed between the reactionplate 36 and the shrink coupling 32. In the illustrated embodiment, thejacking devices 42 are equally spaced around the circumference of theshaft 42 and have a first end (not visible in FIG. 2) engaged againstthe head plate 40, and an opposite engagement end 46 configured in apull-engagement with the shrink coupling 32.

The first end of the jacking devices 42 may be rigidly connected to thehead plate 40. In this embodiment, the head plate 40 may be provided insections with the jacking devices 42 rigidly attached thereto. Forexample, the head plate 40 may be provided in three circumferentialsections, with a jacking device 42 attached to each section. Thesections may then be assembled around the circumference of the shaft 22so that the three jacking devices 42 are equally spaced around the shaft22.

The engagement ends 46 of the jacking devices 42 may be configured inthe pull-engagement with the shrink coupling 32 in various ways. Forexample, in the illustrated embodiment, the engagement end 46 of thejacking devices 42 includes a hook 48. This hook 48 engages in eye bolts50 that are substituted for head bolts 34 in the shrink coupling 32. Inother words, a plurality of circumferentially equally spaced head bolts34 may be removed from the shrink coupling 32 and eye bolts 50 threadedinto the shrink coupling 32 in place of the head bolts 34. In analternate embodiment, the engagement end 46 of the jacking devices 42may include a threaded member that threads directly into the threadedbores in the face of the shrink coupling 32. It should be appreciatedthat any manner of pull-engagement configuration may be utilized in thisregard to mechanically couple the engagement end 46 of the jackingdevices 42 with the shrink coupling 32. It should also be appreciatedthat the eye bolt 50 and hook 48 engagement configuration illustrated inFIG. 2 may be reversed so that the hooks 48 are threaded into bores inthe shrink coupling 32, and eye bolts 50 are configured on theengagement ends 46 of the jacking devices 42.

The system 35 may also include a shim member 54 that is provided on theshaft 22 at an axial position between the shrink coupling 32 andreaction plate 36. This shim member 54 may be made from any suitablerigid material that has a shape or physical property so as to conform tothe circumference of the shaft 22. In a particular embodiment, the shimmember 54 may be modular in nature in that it is formed from a pluralityof suitable composite material pieces that are assembled at leastpartially around the upper circumferential section of the shaft 22. Theshim member 54 should be of sufficient rigidity and strength so as tofully support the weight of the shrink coupling 32 on the shaft 22. Asdescribed in greater detail below, once the shrink coupling 32 has beenremoved from the gearbox 30, the coupling 32 is pulled axially onto theshim member 54 to a rest position on the shaft 22. The shim member 54has a radial thickness such that the shrink coupling 32 is maintained inan aligned concentric relationship with the gearbox 30 (sleeve 31) whileat its resting position on the shim member 54 (and shaft 22). Inembodiments wherein the shaft 22 has a stepped circumferential contour,the shim member 54 would have a correspondingly shaped stepped profileso that the shrink coupling 32 is maintained in an aligned concentricrelationship with respect to the gearbox sleeve 31.

The system 35 is not limited to any particular type of jacking device42. In a particular embodiment, the jacking devices 42 may be portablehydraulic jacks that are supplied with pressurized hydraulic fluid froma suitable source. For example, in the embodiment wherein the system 35is utilized within a wind turbine nacelle 14, a portable hydraulic pump,reservoir, and manifold may be brought into the nacelle 14 for thispurpose. Desirably, the individual hydraulic jacks 44 are supplied froma common manifold header to ensure that the jacks are equallypressurized.

It is desirable that the jacking devices 42 are reversible inoperational direction so that the same jacking devices 42 may be used tosubsequently re-attach the shrink coupling 32, as described in greaterdetail below.

FIGS. 4 through 6 are sequential operational views of the system 35being used to remove the shrink coupling 32 from a turbine generatorgearbox 30. FIG. 4 illustrates initial preparation of the gear traincomponents. In particular, certain of the head bolts 34 in the shrinkcoupling 32 have been removed and replaced with eye bolts 50. Also, theshim member 54 has been assembled around at least a portion of thecircumference of the main rotor shaft 22. It should be appreciated thatit is not necessary to assemble the shim member 54 completely around theshaft 22. The shim member 54 is used to support the shrink coupling 32on a shaft 22 in concentrically aligned relationship with the gearboxsleeve 31 and, in this regard, need only extend partially around theshaft 22, for example about halfway around the shaft 22.

FIG. 5 illustrates the system 35 after the reaction plate 36 has beenassembled and anchored axially in position relative to the shrinkcoupling 32 at anchor points 38. The jacking devices (hydraulic jacks 44in this embodiment) are equally spaced around the head plate 40 andhooks 48 at the engagement end 46 of the hydraulic jacks 44 are engagedwith the eye bolts 50. At this stage, the shrink coupling 32 has beenreleased from its clamped state by conventional means. The hydraulicjacks 44 are then actuated to apply a pulling force on the shrinkcoupling 32 in the direction of the arrows indicated in FIG. 5. Theshrink coupling 32 is controllably pulled from the gearbox sleeve 31 toa resting position on the shim 54 (and shaft 22) as illustrated in FIG.6. The shrink coupling 32 may remain in this position while any mannerof maintenance procedure is performed on the gearbox 30.

Once maintenance procedures are completed on the gearbox 30, the shrinkcoupling 32 may be re-attached utilizing the system 35. This process isconceptually illustrated in the sequential views of FIGS. 7 through 9.The jacking devices (hydraulic jacks 44 in this embodiment) areconfigured in a push-engagement at the engagement end 46 with the shrinkcoupling 32 and are reversed in direction as indicated by the arrows inFIG. 7. The shrink coupling 32 is maintained in an aligned concentricrelationship with respect to the gearbox sleeve 31 and, thus, can bemechanically pushed into the sleeve 31 by the action of the hydraulicjacks 44, as illustrated in FIG. 8. At this stage, the shrink coupling32 may be actuated to its clamped configuration by conventional means,and the system 35 removed from the drive train components, as depictedin FIG. 9.

FIG. 3 is similar to the view of FIG. 2 but illustrates a particulartype of push-engagement configuration at the ends 46 of the jackingdevices 42 that may be useful for re-attaching the shrink coupling 32 inthe procedure illustrated in FIGS. 7 through 9. In this embodiment, thehooks 48 have been removed from the engagement ends 46 and a push plate52 substituted therefore. Also, the eye bolts 50 have been removed fromthe shrink coupling 32 and replaced with the appropriate head bolts 34or jacking screws. In this embodiment, the push plates 52 simply engageagainst the head bolts 34 and axially push the shrink coupling 32 intoengagement with the gearbox 30. It should be appreciated, however, thatany other manner of push-engagement configuration between the jackingdevices 42 and front face of the shrink coupling 32 may be utilized forthis purpose.

The present invention also encompasses a method for removing a shrinkcoupling in accordance with certain aspects discussed above. The methodincludes, for example, erecting a reaction plate around the shaft at alocation displaced from the shrink coupling, and anchoring the reactionplate axially in place relative to the shaft. A plurality of jackingdevices are disposed between the reaction plate and the shrink coupling,and are equally circumferentially spaced around the shaft. The jackingdevices have a first end that is engaged against the reaction plate, anda second opposite end that is in a pull-engagement configuration withthe shrink coupling. The shrink coupling is released from its clampedstate and the jacking devices are actuated to exert a pulling force onthe shrink coupling. The shrink coupling is pulled off of the drivetrain component and moved axially along the shaft to a resting positionon the shaft.

The method may also include providing a shim member around at least aportion of the circumference of the shaft at a location axially betweenthe shrink coupling and the reaction plate. The shrink coupling ispulled onto the shim member in its resting position on the shaft. Theshim member is constructed to have a radial thickness such that theshrink coupling is maintained in an aligned concentric relationship withthe drive train component at its resting position on the shim member.

The method may further include erecting the reaction plate around themain drive shaft from a plurality of individual frame members. Thismethod may be particularly useful in practice of the method within arelatively confined nacelle of a wind turbine, wherein individualcomponents of the reaction plate would need to be brought into theturbine nacelle and subsequently erected.

The method may further include moving the shrink coupling from its restposition on the shaft back into an operational position on the drivetrain component by reversing the direction of the jacking devices andmoving the shrink coupling axially along the shaft to its finaloperational position. At this stage, the shrink coupling can be actuatedto its clamped state and any devices used in the method removed from thedrive train components.

While the present subject matter has been described in detail withrespect to specific exemplary embodiments and methods thereof, it willbe appreciated that those skilled in the art, upon attaining anunderstanding of the foregoing may readily produce alterations to,variations of, and equivalents to such embodiments. Accordingly, thescope of the present disclosure is by way of example rather than by wayof limitation, and the subject disclosure does not preclude inclusion ofsuch modifications, variations and/or additions to the present subjectmatter as would be readily apparent to one of ordinary skill in the art.

1. A system for removing a shrink coupling that secures a shaft to adrive train component, said system comprising: a reaction plate erectedaround said shaft at a location displaced from said shrink coupling,said reaction plate anchored in place relative to said shaft; aplurality of jacking devices operationally disposed between saidreaction plate and said shrink coupling, said jacking devices equallycircumferentially spaced around said shaft and having a first endengaged against said reaction plate and a second opposite endmechanically fastened in a pull-engagement configuration to said shrinkcoupling; and whereby to remove said shrink coupling from said drivetrain component, said shrink coupling is released from a clamped stateand said jacking devices are activated to exert a pulling force on saidshrink coupling until said shrink coupling is pulled off of said drivetrain component and moved axially along said shaft to a resting positionon said shaft.
 2. The system as in claim 1, further comprising a shimmember disposed circumferentially around at least a portion of saidshaft at an axial location between said shrink coupling and saidreaction plate such that said shrink coupling is pulled onto said shimmember in the resting position of said shrink coupling on said shaft,said shim member having a radial thickness such that said shrinkcoupling is maintained in an aligned concentric relationship with saiddrive train component at the resting position of said shrink coupling onsaid shaft.
 3. The system as in claim 1, wherein said system isconfigured for removing a shrink coupling in a wind turbine nacelle,said shaft comprising a main drive shaft and said drive train componentcomprising a gearbox, said reaction plate anchored to a bedplate in saidwind turbine nacelle.
 4. The system as in claim 3, wherein said jackingdevices comprise hydraulic jacks.
 5. The system as in claim 4, whereinsaid reaction plate comprises a plurality of separate frame membershaving a size and configuration so as to be moved into said wind turbinenacelle and constructed around said main drive shaft.
 6. The system asin claim 1, further comprising a plurality of threaded engagementmembers that are threaded into equally circumferentially spaced boltholes in a front face of said shrink coupling, said second end of saidjacking devices comprising a complimentary engagement member thatengages with said threaded engagement members in a pull-engagementconfiguration.
 7. The system as in claim 6, wherein said threadedengagement members comprise one of a hook or an eye, and said second endof said jacking devices comprises a complimentary eye or hook,respectively.
 8. The system as in claim 1, wherein said jacking devicesare reversible and said second end of said jacking devices areconfigurable into a push-engagement with said shrink coupling, wherebysaid shrink coupling is movable from its rest position on said shaftback into position for securing said shaft to said drive train componentby reversing the direction of said jacking devices and moving saidshrink coupling axially along said shaft and into an operationalposition on said drive train component.